Modelling and analysis of a collision avoidance protocol using Spin and Uppaal

This paper compares the tools SPIN and UPPAAL by modelling and verifying a Collision Avoidance Protocol for an Ethernet–like medium. We find that SPIN is well suited for modelling the untimed aspects of the protocol processes and for expressing the relevant (untimed) properties. However, the modelling of the media becomes ackward due to the lack of broadcast communication in the PROMELA language. On the other hand we find it easy to model the timed aspects using the UPPAAL tool. Especially, the notion of committed locations supports the modelling of broadcast communication. However, the property language of UPPAAL lacks some expessivity for verification of bounded liveness properties, and we indicate how timed testing automata may be constructed for such properties, inspired by the (untimed) checking automata of SPIN.